JSON to TypeScript Types Converter Tool
Paste JSON or a JavaScript object and instantly get TypeScript interfaces. Free, private, and runs entirely in your browser.
Input: JSON or a JS object 👇
Output: TypeScript Types 👇
How to Convert JSON to TypeScript
- Paste your JSON into the left editor. You can also paste a JavaScript object literal — unquoted keys and trailing commas are accepted.
- TypeScript interfaces appear instantly in the right panel. Nested objects are automatically extracted into separate named interfaces.
- Click "Copy to Clipboard" and paste the generated types into your
.tsor.d.tsfile.
Why Convert JSON to TypeScript?
TypeScript's type system catches bugs at compile time rather than at runtime. When you work with JSON data — from REST APIs, configuration files, or databases — defining TypeScript interfaces ensures your code correctly handles every field and data type.
Manually writing interfaces for large JSON payloads is tedious and error-prone. This converter automates the process: paste a sample JSON response and get production-ready TypeScript types in seconds.
Features
- Instant conversion — types update as you type, no submit button needed
- Nested object support — deeply nested structures are split into clean, named interfaces
- Array type inference — arrays of objects, primitives, and mixed types are handled correctly
- JavaScript object support — accepts unquoted keys, single quotes, and trailing commas
- 100% client-side — your data never leaves your browser
- Syntax-highlighted editors — CodeMirror-powered editors with line numbers for both input and output
- One-click copy — copy generated types to clipboard instantly
Common Use Cases
API Response Typing
Copy a sample response from your REST API, GraphQL endpoint, or third-party service and generate TypeScript interfaces for type-safe data fetching.
Configuration Files
Convert JSON config files (tsconfig.json, package.json, custom configs) into typed interfaces for safer config parsing.
Database Documents
Paste a MongoDB document, Firestore record, or any JSON-based database output to quickly generate model types for your data access layer.
Frequently Asked Questions
How do I convert JSON to TypeScript?
Paste your JSON into the left editor panel. TypeScript interfaces are generated instantly in the right panel. Click "Copy to Clipboard" to use the generated types in your project.
Does this tool support nested JSON objects?
Yes. The converter handles deeply nested objects, arrays, arrays of objects, mixed types, and optional fields. Each nested object gets its own named interface.
Can I convert a JavaScript object (not just JSON)?
Yes. The input parser accepts both strict JSON and JavaScript object literals, including unquoted keys, trailing commas, and single-quoted strings.
Is my data sent to a server?
No. All conversion happens entirely in your browser using client-side JavaScript. Your JSON data never leaves your machine.
What is the difference between a TypeScript interface and a type?
Interfaces and types are largely interchangeable in TypeScript. Interfaces are better for describing object shapes and can be extended or merged. Types are more flexible and can represent unions, intersections, and primitives. This tool generates interfaces, which is the recommended pattern for object shapes.